Some conventional vehicle power supply apparatuses are configured to classify a plurality of electrical loads into a predetermined number of groups, then to distribute power supplied from a power supply is to each group in accordance with a priority level (group priority level) defined for the group and to distribute the power distributed to a specific group to each electrical load within the group in accordance with a priority level (load priority level) defined for the electrical load within the group (for example, see PTL 1). The group priority level and the load priority level are calculated based on information relating to the vehicle states such as a warm-up state of the vehicle and the external illuminance of the periphery of the vehicle.